Study: Humans Have Evolved To Naturally Fear Spiders, Snakes

November 10, 2017 5:45 PM

CBS Local — Even though Halloween has come and gone in 2017, the human revulsion for creepy crawlers is apparently here to stay.

A new report says a study of babies has found that humans don’t just learn to be scared of spiders and snakes, they are actually born with the fear of those creatures already in their brains. The report, published in Frontiers in Psychology, tracked the responses of a group of six-month-olds when they were shown images of the frightening animals compared to images of fish and flowers.

Scientists from Germany and Sweden say the babies’ eyes opened much wider when presented with the spiders or snakes, signaling the human “fear-threat reaction” at work.

“Change in size of the pupils is an important signal for the activation of the noradrenergic system in the brain, which is responsible for stress reactions,” neuroscientist Stefanie Hoehl said in a press release. “Accordingly, even the youngest babies seem to be stressed by these groups of animals.”

The researchers theorize that the results seen in the 32 infants show that humans have grown to view these scary-looking creatures as a danger and have passed that fright down to their ancestors.

“This particular reaction upon seeing spiders and snakes is due to the coexistence of these potentially dangerous animals with humans and their ancestors for more than 40 to 60 million years,” Hoehl added.

The study added that combining this inherited fear of scary critters with other factors, like your parents’ reactions or if your brain has an overactive “fight-or-flight” response, can lead to a person suffering from a severe phobia of spiders and snakes.